There’s a widely held skepticism about MSG that started with a letter published in the New England Journal of Medicine (NEJM) in 1968. In an opinion piece, a physician noted radiating pain in his arms, weakness and heart palpitations after eating at Chinese restaurants, and speculated that cooking wine, MSG or excessive salt might be to blame. Readers replied that they too experienced this “Chinese Restaurant Syndrome,” and MSG became suspect in the public eye. Its presence at the top of people’s minds has ebbed and flowed over the past 50 years, but it is in the public consciousness enough that quite a few food labels today still tout a food’s MSG-free status.

But is MSG bad for you? Let’s take a look at what the science has to say.

Brain. Concerns about MSG’s effect on the brain come from a study conducted in the late 1960’s. In the study, huge doses of MSG were injected into neonatal mice, and the mice were found to develop neurological problems. But, this study doesn’t relate to the real world because people consume MSG by eating small amounts of it rather than injecting large doses. To follow up on this study, several more studies were done using large doses of glutamate taken by mouth. None of this research was able to replicate the findings from the one earlier study, and it all failed to show any link between eating MSG and experiencing neurological side effects.

Because free glutamate plays such an important role in brain function – allowing nerve cells to talk to other cells – the interaction between the brain and glutamate has been extensively studied. What scientists have found is that the brain maintains tight control over the amount of glutamate within it, and the amount of glutamate eaten by a person and/or in a person’s blood doesn’t affect how much glutamate is in their brain.

Headaches. Migraines are a debilitating type of headache. The causes, which are not well understood, are thought to be due to personal (genetics, brain chemicals, hormones, etc.) and environmental (food, stress, sleep, etc.) factors. Although MSG is often included in migraine “trigger lists” along with other foods like chocolate and cheese, there is no research that shows MSG causes migraines/headaches. In fact, the Journal of Headache and Pain removed MSG as a headache trigger back in 2016. A review paper published in the Journal of Headache and Pain looked at the research done on MSG and headaches and determined, “it would be premature to conclude that the MSG present in food causes in headache.” On the topic, the FDA (United States Food and Drug Administration) says, “Over the years, FDA has received reports of symptoms such as headache and nausea after eating foods containing MSG. However, we were never able to confirm that the MSG caused the reported effects.”

Asthma. An early poorly controlled study suggested that MSG might provoke an asthma attack. Since then numerous well-controlled, blinded studies have not been able to reproduce those results and have concluded that MSG does not induce asthma.

Allergy. A food allergy is a harmful response to a food protein triggered by the immune system. It happens consistently anytime the allergic person is exposed to that food protein (allergen). Because glutamate is an amino acid, not a full protein, it cannot trigger an allergy. In 1991, the American College of Allergy, Asthma and Immunology reviewed the research and concluded that MSG is not an allergen.

Intolerance. A multitude of studies have investigated whether eating MSG could cause symptoms like those associated with “Chinese Restaurant Syndrome.” Some early studies in which participants knew they were consuming MSG reported side effects, but later, better designed studies — where participants didn’t know whether they were getting MSG or a placebo — generally showed no effects. The research as a whole suggests that a small subset of people might have some minor fleeting reactions to large doses of MSG taken on an empty stomach, but that when MSG is consumed as it typically would be – in small amounts within food – there are no side effects.

All glutamate, whether inherently in foods or added with MSG, is treated in the same way by the body.

All glutamate, whether inherently in foods or added with MSG, is treated in the same way by the body. Much of it is used as fuel by the cells in the GI tract, and the rest of it is used for metabolism or to make proteins in our bodies. Our bodies can also make glutamate if it does not receive enough from food. If MSG were to cause problems in our bodies, then any foods high in free glutamates would also be expected to cause the same problems. But this is not what happens in the real world, and a multitude of research backs this up. Based on the extensive scientific data, it’s clear that seasoning your food with MSG is safe.

“Oh, we always make sure to ask for no MSG when we eat Chinese food.” “I never allow my kids to eat anything with MSG.” “It’s horrendous that MSG is even allowed to be used in food that could be given to kids.” These are comments I’ve actually heard from consumers and patients. What these same consumers have actually done is let me know they are very misinformed.

Takasaki Y. Studies on brain lesions after administration of monosodium L-glutamate to mice. II. Absence of brain damage following administration of monosodium L-glutamate in the diet. Toxicology. 1978;9(4):307-318

About
Theresa Hedrick, MS, RD

Theresa is a dietitian in private practice who specializes in GI disorders and food allergies and intolerances. She is passionate about making nutrition fit within the constraints of the real world. Theresa previously spent years coaching heart patients at Emory University Hospital Midtown through lifestyle changes as well as teaching students at Oregon State University and Georgia State University the basics of nutrition. Read more about her background on the About page.

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